This paper generalizes the load scaling techniques proposed in (Kuo and Mok, 1991) for fixed-priority real-time applications. A framework is proposed to adjust the system workload by relating the criticality and flexi...
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ISBN:
(纸本)081869209X
This paper generalizes the load scaling techniques proposed in (Kuo and Mok, 1991) for fixed-priority real-time applications. A framework is proposed to adjust the system workload by relating the criticality and flexibility of a process to the resource allocation problem. A load adjustment procedure based on the approximation algorithm (Ni et al., 1997) is proposed to maximize the system profit in an on-line fashion. When the list of allowable configurations is implicitly given by scalable periodic processes, the corresponding load filtering problem is shown to be NP-complete. We also prove the upper bound of the system profit and provide a mechanism to balance the schedulability and the maximum profit of the system.
This document1 contains definitions of a wide range of concepts specific to and widely used within temporal databases. In addition to providing definitions, the document also includes explanations of concepts as well ...
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The transportation of prerecorded, compressed video data without loss of picture quality requires the network and video servers to support large fluctuations in bandwidth requirements. Fully utilizing a client-side bu...
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The transportation of prerecorded, compressed video data without loss of picture quality requires the network and video servers to support large fluctuations in bandwidth requirements. Fully utilizing a client-side buffer for smoothing bandwidth requirements can limit the fluctuations in bandwidth required from the underlying network and the video-on-demand servers. This paper shows that, for a fixed-size buffer constraint, the critical bandwidth allocation technique results in plans for continuous playback of stored video that have (1) the minimum number of bandwidth increases, (2) the smallest peak bandwidth requirements, and (3) the largest minimum bandwidth requirements. In addition, this paper introduces an optimal bandwidth allocation algorithm which, in addition to the three critical bandwidth allocation properties, minimizes the total number of bandwidth changes necessary for continuous playback. A comparison between the optimal bandwidth allocation algorithm and other critical bandwidth-based algorithms using 17 full-length movie videos and 3 seminar videos is also presented.
A distributed computing system consists of heterogeneous computing devices, communication networks, operating system services, and applications. As organisations move toward distributed computing environments, there w...
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A distributed computing system consists of heterogeneous computing devices, communication networks, operating system services, and applications. As organisations move toward distributed computing environments, there will be a corresponding growth in distributed applications central to the enterprise. The design, development, and management of distributed applications presents many difficult challenges. As these systems grow to hundreds or even thousands of devices and similar or greater magnitude of software components, it will become increasingly difficult to manage them without appropriate support tools and frameworks. Further, the design and deployment of additional applications and services will be, at best, ad hoc without modelling tools and timely data on which to base design and configuration decisions. This paper presents a framework for management of distributed applications and systems. The framework is based on a set of common management services that support management activities. The services include monitoring, control, configuration, and data repository services. A prototype system built on the framework is described that implements and integrates management applications providing visualisation, fault location, performance monitoring and modelling, and configuration management. The prototype also demonstrates how various management services can be implemented.
An early version of the Z Standard included the deductive system W for reasoning about Z specifications. Later versions contain a different deductive system. In this paper we sketch a proof that W is relatively sound ...
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ISBN:
(纸本)3540627170
An early version of the Z Standard included the deductive system W for reasoning about Z specifications. Later versions contain a different deductive system. In this paper we sketch a proof that W is relatively sound with respect to this new deductive system. We do this by demonstrating a semantic basis for a correspondence between the two systems, then showing that each of the inference rules of W can be simulated as derived rules in the new system. These new rules are presented as tactics over the the inference rules of the new deductive system.
Knowledge-Based systems (KBS) are developed to contain substantial elements of human knowledge and expertise in a well-defined domain, and use these to support user or expert tasks. Issues related to the social and or...
Knowledge-Based systems (KBS) are developed to contain substantial elements of human knowledge and expertise in a well-defined domain, and use these to support user or expert tasks. Issues related to the social and organisational contexts of these systems are widely acknowledged to be particularly critical to their success. However, methodology proposals usually stop short of adequately handling soft and unstructured data that frame the contexts of use. The handling of qualitative data needs to be done in a way that directly impinges on the wider Knowledge-Based System engineering processes and decisions. In this paper, we discuss the nature of context-sensitive issues, and describe a methodological approach for resolving them through the rigorous analysis of qualitative data, using a methodology which is based upon the Grounded Theory method from the social sciences.
High-level reusability has been achieved in software architecture using design patterns. In this paper, two different applications are presented using design patterns in the system analysis and design cycle. It is con...
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High-level reusability has been achieved in software architecture using design patterns. In this paper, two different applications are presented using design patterns in the system analysis and design cycle. It is concluded that software development using design patterns greatly reduces the design time and reduces the risk of design error.
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